n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 0 |
4 | 1 |
5 | 2 |
6 | 5 |
7 | 17 |
8 | 49 |
9 | 138 |
10 | 374 |
11 | 1062 |
12 | 2851 |
13 | 8010 |
14 | 21432 |
15 | 60142 |
16 | 161386 |
17 | 453253 |
18 | 1222110 |
19 | 3436564 |
20 | 9316409 |
21 | 26231463 |
22 | 71496106 |
[0,0,0,1,2,5,17,49,138,374,1062,2851,8010,21432, 60142,161386,453253,1222110,3436564,9316409, 26231463,71496106] |